Title: Nitroxyl-mediated oxidation of lignin and polycarboxylated products

Abstract

Methods of selectively modifying lignin, polycarboxylated products thereof, and methods of deriving aromatic compounds therefrom. The methods comprise electrochemically oxidizing lignin using stable nitroxyl radicals to selectively oxidize primary hydroxyls on .beta.-O-4 phenylpropanoid units to corresponding carboxylic acids while leaving the secondary hydroxyls unchanged. The oxidation results in polycarboxylated lignin in the form of a polymeric .beta.-hydroxy acid. The polymeric .beta.-hydroxy acid has a high loading of carboxylic acid and can be isolated in acid form, deprotonated, and/or converted to a salt. The .beta.-hydroxy acid, anion, or salt can also be subjected to acidolysis to generate various aromatic monomers or oligomers. The initial oxidation of lignin to the polycarboxylated form renders the lignin more susceptible to acidolysis and thereby enhances the yield of aromatic monomers and oligomers obtained through acidolysis.

Inventors:

Stahl, Shannon S.; Rafiee, Mohammad

Issue Date:

2018-02-27

Research Org.:

Wisconsin Alumni Research Foundation, Madison, WI (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1423443

Patent Number(s):

9,903,028

Application Number:

15/167,053

Assignee:

WISCONSIN ALUMNI RESEARCH FOUNDATION (Madison, WI)

DOE Contract Number:  

FC02-07ER64494

Resource Type:

Patent

Resource Relation:

Patent File Date: 2016 May 27

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY